This study seeks to explain the mechanisms underlying house staff's attitudes and subsequent behaviors concerning AIDS, utilizing a longitudinal design and building on baseline data collected in 1989. Analysis of the 1989 data revealed that residents are consistently more negative in their attitudes toward a wide range of AIDS issues than fourth-year medical students and report greater intention to avoid AIDS in future practice. Hypotheses about the causes of such disparities rely, to varying degrees, upon (1)the potential impact of factors associated with the training experience as students progress through internship and further graduate training, and (2)the possible effects of individual characteristics which differentiate the younger cohort of trainees from their earlier counterparts. The proposed research is designed to identify the relative importance of aspects of training as well as characteristics of the cohorts in explaining physicians' attitudes toward AIDS and their relationship to subsequent behaviors. The goal of the research is to generate an incisive understanding of that portion of attitude formation which is alterable and to inform strategies for purposeful intervention. The longitudinal design, following a sample of 1989 medical graduates and interviewing a companion cohort of the 1989 PGY-2 sample, will permit a delineation of cohort- and socialization-effects. This distinction is important since the mechanisms have different implications for the development of strategies for change. In-depth knowledge of how training affects AIDS attitudes and how those attitudes affect day-to-day behavior and future plans will lead to identification of aspects of training whose modification would be beneficial in promoting more positive outlooks. A knowledge of cohort differences may be important in targeting particular types of students in recruitment efforts and in alerting educators to issues which might be addressed in training so as to shape emerging attitudes toward AIDS. The study is intended to provide medical educators with specific recommendations for training physicians who have a more positive outlook toward treating patients with AIDS.